Take this number
x 0.2 if you are sedentary
x 0.3 if you are lightly active
x 0.4 if you are moderately active
x 0.5 if you are extremely active

Add this number to your BMR

This will give you your recommended calorie intake per day if you want to maintain your current weight

Subtract 500 calories per day to result in an approximate 1 lb/wk weight loss.

The important thing to remember is that you should recalculate your BMR as you lose weight. This formula should be used with a three to five times a week moderate to heavy exercise regimen of mixed cardio and weights.

I've found that the above formula used with a ratio of 50% carbs to 25% fat and 25% protein and a moderate workout regimen results in around a one pound weight loss per week for me. Fit Day does an awesome job of helping me keep up with my fitness and weight goals

I had estimated my calories needed to lose weight at about 1500. Your formula (minus the activity adjustment) calculated that I should consume about 1550 calories to lose a pound a week. Seems like I'm on the right track! Thanks for the formula - it looks like a winner.